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@me2621a, I've had a chance to go back and read your impressions on the TS 6SU7 - both in this thread, and in the NOS 6SL7 thread. Thanks for posting those.

It sounds like you found the 6SU7 and the 6SU7/6550/SED Black plate combo to be more resolving, and overall preferred them vs some other popular NOS tube. All of which sounds quite interesting - and tempting of course. Thanks a lot for that (kidding ).

Interesting to read that you found the Mogwai a good match with the Utopias - I can imagine how that would be a very good match .Good to know.

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Yah I am a big fan of the SU7/6550 combo. For the the rectifier, that is a bit tougher, with the Gumby the SED is perfect as it brightens up the presentation slightly, with something that is already a little bright like my Vega G2, the RCA is far better, but the RCA made the Gumby mushy, where the SED made the Vega slightly shrill. All incredibly subtle, but that is the fun of the hobby right?

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Yah I am a big fan of the SU7/6550 combo. For the the rectifier, that is a bit tougher, with the Gumby the SED is perfect as it brightens up the presentation slightly, with something that is already a little bright like my Vega G2, the RCA is far better, but the RCA made the Gumby mushy, where the SED made the Vega slightly shrill. All incredibly subtle, but that is the fun of the hobby right?

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Great info, thanks. I'm still likely to switch headphones at some point (although I may take my time to figure out which direction to go, esp to pair with the Mogwai), so I'm not sure whether or how I'll want to tweak the amps signature just yet.

Regarding the Utopias, I understand that there are at least two versions - the original, and a more bass prominent version. Do you know which version you have that you like with the Mogwai?

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Hey guys,
Anyone using 6L6GCs in their Mogwai or Mogwai SE? I had been running a pair of Bendix 6384s and really like the sounds but hate the way they look with the adapters (silly that it matters but it sadly does to me).

I just ordered a pair of NOS Tung-Sol (GE made) 6L6GCs and I am excited to give them a listen, but I am curious if people are using them and what they think?

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Great info, thanks. I'm still likely to switch headphones at some point (although I may take my time to figure out which direction to go, esp to pair with the Mogwai), so I'm not sure whether or how I'll want to tweak the amps signature just yet.

Regarding the Utopias, I understand that there are at least two versions - the original, and a more bass prominent version. Do you know which version you have that you like with the Mogwai?

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I believe I have a later version (bought new July 4th of 2018). I did not know there were multiple versions of the utopia, I will say it is a great headphone and sounds great out of both the 8ohm and 32 ohm tap.

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@ampsandsound I see why. It tool me a long time to like the Bendix but I am not really into it, and the GE 6l6 sounds great as well.

I am trying to figure something out though. I am getting a hum through the Mogwai SE that seems like it was not their before. Swapping tubes sometimes fixes it, and other times doesn't.

For example:
Replace Power tubes (El34 -> 6l6) louder hum. Hum does not change volume when turning the volume up or down and is present when the volume is all the way down.
Replace Pre-Amp tube (NOS TS 6SL7 -> JJ 6SL7) hum decreases but does not go away
Replace Pre-Amp tube again (JJ -> NOS TS), hum is back to the lower level.

In all cases hum is still present even when the volume is at 0 on the amp. It is not coming from the source (unplugged the source cables, and use the input transformer between them). Power goes through a Furman Power Conditioner. At first I thought the hum was maybe because I was using the 32 ohm tap instead of the 8ohm tap. But even the 8ohm tap has a hum that is fainter, but still loud enough to be herd in quiet passages. It also seems to be present with tube configurations that never had any background noise before. Any thoughts on what could be causing this? Could something have happened to the Biasing circuit, or maybe a tube socket could have come loose?

Member of the Trade: ampasandsound

@ampsandsound I see why. It tool me a long time to like the Bendix but I am not really into it, and the GE 6l6 sounds great as well.

I am trying to figure something out though. I am getting a hum through the Mogwai SE that seems like it was not their before. Swapping tubes sometimes fixes it, and other times doesn't.

For example:
Replace Power tubes (El34 -> 6l6) louder hum. Hum does not change volume when turning the volume up or down and is present when the volume is all the way down.
Replace Pre-Amp tube (NOS TS 6SL7 -> JJ 6SL7) hum decreases but does not go away
Replace Pre-Amp tube again (JJ -> NOS TS), hum is back to the lower level.

In all cases hum is still present even when the volume is at 0 on the amp. It is not coming from the source (unplugged the source cables, and use the input transformer between them). Power goes through a Furman Power Conditioner. At first I thought the hum was maybe because I was using the 32 ohm tap instead of the 8ohm tap. But even the 8ohm tap has a hum that is fainter, but still loud enough to be herd in quiet passages. It also seems to be present with tube configurations that never had any background noise before. Any thoughts on what could be causing this? Could something have happened to the Biasing circuit, or maybe a tube socket could have come loose?

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me2621a its nearly impossible for the bias to be the culprit. Its a cathode bias with significantly over spec'd resistors... they don't drift and are unchanged by heat in the application.
Given all you've reported, Id suspect the input tube (6sl7). You might try: unplugging the amp. when tubes are cold, remove from socket. Take windex and a cloth. Spray windex on the cloth, and rub the pins to clean the dust or oxidation off. Let the pins dry for 15min. Reinsert and turn back on.

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AmpsandSound Amplifier Roundup

Preamble and a surprise

During the month of January I started to think about what was next for me on my audio journey. I knew I really liked my Mogwai SE, I had always been curious about 300Bs, and I wanted something that could drive high efficiency speakers as well. I also wanted to replace my Schiit Mjolnir 2 in my office with something closer to a Mogwai SE as I realized that my Mjolnir 2 has gotten almost no use since the Mogwai SE showed up in my house at the beginning of August.

Given my extremely positive experience with Justin and his Mogwai SE I decided to give him a call and discuss with him what I was looking for. The goal was simple, buy an Agartha 2.0, move the Mogwai SE into my office, and have an Agartha 2.0 amp for headphones and eventually speakers when I move to the next house. However because Justin wants you to be happy sometimes these conversations are not as simple as one would expect. He knew that I had been having background noise on my Mogwai SE and asked if it bothered me. When I said it did a bit, he immediately said, the Agartha 2.0 is not for you, it is noisier then the Mogwai and while it is more then fine for speakers and lower efficiency headphones, if the Mogwai SE produces any sort of background noise the Agartha will produce more just because of its topology and its power output. Great save Justin!

He then told me about an exciting new project that he had just begun working on. He was designing monoblocks headphone amplifiers, they were going to be built like tanks, and they were going to be awesome. After he was done describing the feature set to me (which I cannot share at this time, but will once I am aloud to), I was sold on the picture he was painting and I pre-ordered the first production model of his new amplifiers. There were some choices for me to make though, and to help me make those choices Justin sent me his personal Kenzie and personal Leeloo (Solid State Rectified Pendent) so I could listen to the difference between his existing 3 amplifiers to decide if I liked a sound signature with 0 feedback (Mogwai SE and Kenzie) or with some feedback (Leeloo). It also gave me a rare opportunity to listen to all 3 of his amplifiers (sans Agartha) on my own system and have a shoot out of sorts. Given that when I am looking to buy something I find shootouts helpful, I thought I would write about it.

Build Quality

For those who have owned AmpsandSound amplifiers we know that the build quality of their units are exceptional. The plates are laid out carefully, and set into beautiful wood boxes. The fit and finish is second to non and I am constantly surprised at just how well built these amplifiers are. What was impressive to me though was how well built all 3 of these amplifiers are. They all had the same level of attention to detail, they all had beautiful cases, they all seemed to be built like tanks. Given that AmpsandSound is a smaller shop, its great to see this level of consistency in build quality across his amplifiers.

Kenzie - Build Quality and Setup
For me the Kenzie was a big surprise, I knew it was a fairly small amp, and I had seen it in pictures but taking it out of the box was still a bit of a shock. Coming in at about half the size of the Mogwai SE, the best way to describe it was “cute”.

While it is a small amp, it didn’t feel light, it felt dense, like a little package of transformers and tube sockets should feel. Justin’s personal Kenzie shipped with a black wooden case which looked great. Smooth and furniture grade just as I have learned to expect from him.

The tube compliment was the lovely Tung-Sol 1626 for power tubes, and a Raytheon 2C52. I have been told that the 2C52 is the only octal base tube with a Mu of 100 and can give the Kenzie a slight extra push in the midrange. I have no complaints about the tube compliment for the Kenzie, but I will talk more about that in the sound section of this review.

Leeloo (Pendent) - Build Quality and Setup
Unboxing the Leeloo, I did not know what to expect. I had never seen a photo of it and only had the Pendent photos to go off as a reference. The Leeloo sits right in the middle of the Kenzie and Mogwai SE size wise. It’s tube complement was a JJ 12AX7 and 2 NOS American Made EL84s. Weight was tough to gauge. I would guess it weighs more than the Kenzie, but not by much, which makes it feel lighter due to the size difference.

The case work was also different on this one, I believe the wood is still walnut, but it is walnut is edge to edge and once again looks great. The Leeloo also can function as a pre-amp and had 2 inputs making it slightly more versatile than the Kenzie.

While the Leeloo is extremely similar to the Pendent there are a few differences, the first is the rectifier. The Leeloo is solid state where the Pendent is tube rectified. The second is the output impedance. The Pendent runs at 8ohms and 300 ohms, where the Leeloo runs at 32ohms and 300 ohms.

Mogwai SE - Build Quality and Setup
For more details and a more in-depth review of the Mogwai SE please see my review on page 11 of this forum. Everything that is true of the Kenzie and Leeloo are also true of the Mogwai SE. It is incredibly well built, it is the biggest of the 3 amps, and it is by far the heaviest. One of my favorite things to do over the past few days has been to have people try and lift the amp while it has been sitting on the dining room table, it is deceptively heavy.

My Mogwai SE is the latest version from Justin which means I have the 8ohm, 32ohm, and 300ohm headphone jacks. Since this is my personal amplifier I also have a very specific tube complement that I run with it. Currently I am using the TS 6SU7, two TS 6550 no hole grey plates, and a late 40’s RCA Carbon Black Plate 5u4g. I will be honest, it’s a killer tube set, and one that I recommend to any Mogwai SE owner, though finding the to TS 6550 no hole grey plates is getting pretty hard now.

General Setup Notes

All testing and opinions were made using the Vega G2 DAC as a source in streaming mode. All music was either Flac or MQA coming from a Roon server. Single ended RCAs from blue jean cables were used to go from the DAC, into an outboard input transformer, and then a second pair of blue jean RCAs connected the transformer to the amplifier. All components are plugged into a Furman Elite 15pfi Power Conditioner. All listening was done off of the 32 ohm taps with the Focal Utopia headphones.

Listening Tests and Opinions

General Comments

When you speak to Justin, the one thing that will come across pretty quickly is that he likes what he likes, and his products are built to produce the sound he likes. He likes things that are musical and exciting, he likes detail but that is not his focus, his focus is the music. Personally what I found most interesting about comparing these 3 different amplifiers was how similar they were to one another. Justin absolutely has a house sound and I will be honest its a great sound. All of the amps can be described as musical, all of them can be described as full range, and all of them can be described as fun to listen to. There are differences which I will cover, however there are far fewer differences than I personally would have expected going into this comparison. Some might wonder if that is a good thing, and the answer is yes, whether you buy the $1700 Kenzie, the $2000 Leeloo (Pendent), or the $2600 Mogwai SE you get the full Justin Weber experience. Now all that being said there are many things that make the Mogwai SE worth $900 more then the Kenzie, and that make the Leeloo worth $300 more then the Kenzie, but its core features of the amp or small differences that add up to the value difference instead of there being a A team, B team, and C team.

Kenzie
I will be honest. I was really skeptical of the Kenzie when I first plugged it in. All of my amplifiers have been able to output at least a watt of power, and most can produce at least 3 watts. The idea that a 200 mWatt amplifier was going to make my headphones sing was almost laughable…man was I embarrassed when I clicked played. The utopias came alive as they do with my biggest amps. They played high and they played low. They had great mid range and great dynamics. Maybe I lost a bit of slam, but to be honest it made up for it in detail which was surprising as I expected the Kenzie to go a bit flabby in the bass but it didn’t.

The Kenzie has a lovely sound. Its tone is incredible, and things just feel real. It is a really hard amp to write about because when I listen to it, I find myself unable to do anything other then listen to it. It is addicting, I just want to keep listening and keep tapping my foot.

When comparing the Kenzie to the Mogwai SE and Leeloo, they both have slightly more authority, but the Kenzie never feels lacking in that area, where I feel like the Mogwai SE has a vice grip on my headphones, the Kenzie is holding hands with my headphones leading them to where they need to be. Neither is wrong, they are just different. There are moments where I am listening to pop, hip hop, and more recently released music where the vice grip approach is welcome, but especially on well recorded tracks the Kenzies softer approach come across better.

Justin calls the 1626 a mini 300B, while I have personally not spent 100s of ours with 300B amps I get why he says this, the 1626 seems to lend a tone that is really hard to reproduce, the Mogwai SE with my tube complement comes close, but the Kenzie still is the king of tone, given that you can also re-tube the Kenzie for about $45-$60 vs ~$400 for my current tube complement, allows you to get some serious bang for the buck.

The last thing I want to talk about is noise floor. The Kenzie is dead silent, period end of story and for me that is a big deal. Personally I encourage anyone who is thinking about a 300B amp, or thinking about buying an AmpsandSound amp to look at the Kenzie, it is the cheapest option, and honestly its pretty incredible. If I were not buying Justin’s new monoblocks the Kenzie would be remaining in my home, that is how good it is.

Leeloo (Pendent)
I had never listened to an EL84 amp before I listened to the Leeloo. When Justin was describing the difference between the Kenzie and the Leeloo he spoke about two things, the first was power, the Leeloo is much more powerful, and the second was feedback. While the Kenzie and the Mogwai SE are both 0 feedback, the Leeloo has about 6db feedback. Justin informed me that this did two things. The first was produce a quieter background, and the second was create predictability. He said the Leeloo would sound smooth, but to some it may also sound boring.

When I plugged in the Leeloo and let it warm up, I was curious if I would have that reaction. As I put on the first track, I was once again struck by Justin’s house sound, but there was a slight difference, the best way to describe it is vanilla ice-cream vs vanilla soft serve. To be clear I love both and consider them equal, however the experience of eating the two are very different. Ice cream is more textured and sometimes a bit more interesting, where soft-serve is fantastic but you will never be surprised by how big a bite you take. The Kenzie and Mogwai are Ice cream the Leeloo is soft serve. The amp is incredibly capable but where the Mogwai and Kenzie get my toe tapping, the Leeloo leaves my mind wondering and doing other things as the music plays in the background.

I realized about an hour into listening that this would be the perfect amplifier to have in an office or to listen to when working. It produced great music but it didn’t grab me and force me to listen, allowing my focus to fade in and out with what I was doing. The Kenzie and Mogwai SE are the opposite. The Kenzie will grab your attention and not let it go, the Mogwai will do the same, with the added benefit of slapping you with dynamics when your attention gets side tracked for a moment.

I could see the Leeloo working really well with headphones that are aggressive form the start, I imagine that the HD800s would sound great on a Leeloo where personally I think something like the Audeze LCD-3s which are great headphones but already quite smooth would sound boring. The Leeloo for me confirmed that an amp with feedback like this was not quite what I was looking for, but I could see it making some really happy.

Noise floor was very low, slightly higher then the Kenzie but not as high as the Mogwai SE.

Mogwai SE
Again please see my review on page 11 of this forum for more details. The Mogwai SE is a delightful amp. It is powerful, you have a seemingly limitless amount of tube rolling possibilities, and the amps tone, power, dynamics, and detail can be customized with each option. I love this amp. Period end of story. It is awesome, but it is awesomeness varies depending on the tubes you choose, and the headphones you pair it with.

The Mogwai SE is incredibly powerful, but it does have a higher noise floor than the other two amps. On the 8ohm tap that noise floor is pretty non-existent with the Utopias, on the 32 ohm you have to look for it but you can find it. I do not have a pair of headphones that will match correctly on the 300ohm tap so I cannot comment on it. If you have lower efficiency headphones (think planers, or senns) I think the background will be black. With the Utopias which are not actually that hard to drive, the noise does exist, but it is pretty close to black. It is just important to know what you can tolerate, but also to be open. If I had thought any noise would be present I would not have bought this amp. That being said, it would have been a mistake as the Mogwai SE is my favorite amp by fare so I guess you live and learn.

The Mogwai SE is most like the Kenzie (or the Kenzie is most like the Mogwai SE). They are both exciting and engaging. Justin described listening to the Mogwai SE as being in the Music, where the Kenzie is similar to being in the audience. I think that is a correct description after my time with both of them. When I listen to the Mogwai I feel like I am on the stage in the middle of the band, with the Kenzie I feel like they are in front of me. It is not sound staging that changes, though my description sounds like it, its pressure and emphasizes. When the Mogwai SE makes a sound, you know it meant too, there is force behind everything it does. The Kenzie by comparison is almost etherial. When I want Alison Kraus I want a Kenzie, and when I want Ariana Grande I want a Mogwai SE. Both will play either artist with grace and technical proficiency but there is enough of a difference to prefer one over the other in certain instances.

The thing that I both love and hate about the Mogwai SE is the fact that you can roll so many tubes into it. I now have a vast collection of TS 6550s, Mullard EL34s, TS 6su7s, Mullard ecc35s, 6sl7s, 5u4gs, and 5ar4s. Each tube changes the sound of the Mogwai SE slightly. Sometimes for the better and other times for the worst. Having this much flexibility allows you to create some pretty amazing combinations, and allows you to tweak the amp for your mood. It also can lead to indecision, and to a tube buying habit that will have others like in my case my fiancé looking at me like I am a crazy person (she is sadly not wrong).

With my configuration the Mogwai SE hits harder, goes higher, and has better tone than the Leeloo, it hits harder and goes higher than the Kenzie, but the Kenzie just barley edges it out on tone. The Mogwai SE is noisier then both the Leeloo and Kenzie. Like with all things there are trade offs.

Concluding Thoughts
I want to thank Justin for letting me demo the Kenzie and Leeloo. It is clear that the Mogwai SE, the Kenzie, and the Leeloo are incredibly capable amps, and can absolutely serve as end game amplifiers if once chooses to use them as such.

Justin’s house sound is not about detail, nor is it really about neutrality, it is about musicality. It is about toe tapping and loving what you are listening to. While these amps are incredibly technically proficient and with the right tubes you can probably make them detail machines that is really not their point. They are drivers of musical enjoyment and love. It took me a very long time after getting into this hobby to realize, for me, that being an audiophile was not about retrieving every detail, but was about tapping my foot and getting lost in the music. If you agree with that overall goal, any of the AmpsandSound amps will delivery that in spades. If you want extreme detail retrieval as well, there may be a tube complement that achieves that, like sticking an adapter and a Telefunken 12ax7 in the Kenzie, or my TS tube set for the Mogwai SE (which I think is pretty detailed), but you will not cover up the house sound which is a toe tapping good time.

I personally think that Kenzie and the Mogwai SE are better amps then the Leeloo because I found it boring. Others opinions may vary but I really like the excitement that the first two amps bring to the table, and the Leeloo seems to lack that same excitement. All that being said it is by design.

For those of you who are trying to decide which amp is right for you I have a few rankings for you to look at to help decide:

Musicality: Kenzie, Mogwai SE, Leeloo

Noise Floor: (Highest to lowest): Mogwai SE, Leeloo, Kenzie

Engaging: Mogwai SE, Kenzie, Leeloo

Versatility: Mogwai SE, Leeloo, Kenzie

Tone: Kenzie, Mogwai SE, Leeloo

Value for Money: Kenzie, Mogwai SE, Leeloo

I cannot stress this enough, all of these amps are great choices. The Kenzie is a big surprise. If your headphones will work properly on a Kenzie then I personally think a Kenzie should be your first choice. It is the cheapest option and it is just plain addicting. If you like to roll tubes and you want something beefy that will power any headphone and high efficiency speakers, the Mogwai SE is excellent, I have no plans to every replace it. I personally cannot recommend the Leeloo as it did not do it for me, but for those with harsh headphones or with lower quality recording I think they will find the Leeloo a good fit.

To bring it all home, I am excited for what comes next from Justin Webber, his amplifiers are impressive and to have the opportunity to enjoy his 3 primary models in my home has been a great experience. After listening to the lineup I have no regrets for choosing the Mogwai SE, and I will be honest I am still trying to find a spot to put the Kenzie in so I do not have to return it later this week. I am also even more excited for the new amplifiers that I will receive from him over the next month or so. I hope everyone enjoyed this review. If you have thoughts on how I can improve this please let me know.

One other note, it may seem like for the most part I only had good things to say, honestly its true. Justin Webber and his amps are pretty amazing, and with the exception of the Leeloo they do everything that I want them to do. Do I wish I could have a 4 pin XLR output yes, do I wish the ports were on the back instead on on the top, yes, but none of these things matter that much to me anymore, especially after listening to them.

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Super kind words.
To share a bit more... Ive been working on 2 new exciting amps. My hope is they will showcase our work on the highest order.
If all goes well Ill have pics and bench reports to share in 30 days.
Short version... mono blocked... tube PS, more tube rolling choices... lots of impedance choices and wiring that makes me beam.

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me2621a, thank you kindly for this very comprehensive and descriptive review of ampsandsound amps! I have my Kenzie amp which I originally bought
to power my Mr. Speakers Ether phones, a great combo... However I am a longtime Grado fan, and came into a small inheritance after my dad's passing,
so it was easy to dedicate my purchase of PS2000e's to dad's memory. I am not going to go into electrostatics, due to budgetary restraints, so this combo is my end game. I have a friend with a great deal of experience with high end phones, and says these phones and this amp are right at the top of $4000 head phones.
$4400 for both, I'm happy and blessed!

100+ Head-Fier

me2621a, thank you kindly for this very comprehensive and descriptive review of ampsandsound amps! I have my Kenzie amp which I originally bought
to power my Mr. Speakers Ether phones, a great combo... However I am a longtime Grado fan, and came into a small inheritance after my dad's passing,
so it was easy to dedicate my purchase of PS2000e's to dad's memory. I am not going to go into electrostatics, due to budgetary restraints, so this combo is my end game. I have a friend with a great deal of experience with high end phones, and says these phones and this amp are right at the top of $4000 head phones.
$4400 for both, I'm happy and blessed!

Doug

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Thanks for the note. A little while back I had a Grado PS1000e that I adored. I hear the 2000e is even better. I could easily see the Kenzie matching nicely with that phone and I completely believe it would perform in the range of my Utopias with the right equipment, I sadly at the time had a more analytical amp which made the 1000e's a little sharp on the top end.